An AP Biology Blog intended for current news in science as well as a tool to review content in preparation for the AP Exam.

Wednesday, March 4, 2009

Chapter 40 Vocab and packet review!

Hey girls! Remember chapter 40 vocab is due tomorrow, and so are test corrections!

Chapter 40 VocabEpithelial tissue: Sheets of tightly packed cells that line organs and body cavities as well as external services.

Columnar: Refers to the shape of epithelial cells that are taller than they are wide

Squamous:An epithelium characterized by its most superficial layer consisting of flat, scale-like cells called squamous cellCollagenous fibers: Glycoprotein fibers found extensively in connective tissue and boneFibroblast: A type of cell in loose connective tissue that secretes the protein ingredients into threads that form the fabric of the clot.

Macrophages: A phagocytic cell present in many tissues that function in innate immunity by destroying microbes and in acquired immunity an antigen-presenting cell.

Interstitial fluid: An internal environment of vertebrates, consisting of the fluid filling the spaces between cells.

Positive feedback: A physiological control mechanism in which a change in a variable triggers mechanisms that amplify the change.Tendon: A fibrous connective tissue that attaches muscle to bone.

Negative feedback: A primary mechanism of homeostasis, whereby a change in a physiological variable triggers a response that counteracts the initial fluctuation.

Abdominal cavity: The abdominal cavity is the body cavity of the human body (and animal bodies) that holds the bulk of the viscera and which is located below (or inferior to) the thoracic cavity, and above the pelvic cavity. It is a part of the abdominopelvic cavity.

Homeostasis: The steady-state physiological condition of the body.

Neuron: A nerve cell; the fundamental unit of the nervous system, having structure and properties that allow it to conduct signals by taking advantage of the electrical charge across its plasma membrane.

Ligament: A fibrous connective tissue that joins bones together at joints.

Osteoblasts: Cells that arises from fibroblasts and are associated with the production of bone.Nervous tissue: Tissue made up of neurons and supportive cells.

Skeletal muscle: Muscle that is generally responsible for the voluntary movements of the body; also called striated muscle.

Smooth muscle: A type of muscle lacking the striations of skeletal and cardiac muscle because of the uniform distribution of myosin filaments in the cell; responsible for involuntary body activities.

In class today we went over the packet, here are some of the harder questions explained:

5. Which of the following pairs are the best examples of homologous structuresANSWER: B. Bat wing and human hand

These both are mammal and share similar DNA. Therefore, have evolved a more recent common ancestor.

19. What probably explains the inclusion of rabbits on this research?ANSWER: D. Mutations to homologous genes

The species that is least related to others is the outgroup. In this situation the rabbit is at least 3.2 percent away from the other mammals, making it the outgroup.

30. If the experimental population of E. coli lacks an F factor ot F plasmid, and if bacteriophage are excluded form the bacterial cultures, then which of these is a means by which beneficial mutations might be transmitted horizontally to other E. Coli cells?ANSWER: C. via transformation

If the E. coli lacks and F factor or F plasmid then it can't be via conjugation. Then if it can't be via conjugation then it can't be via sex pili. Since bacteriaphage are excluded from the bacterial cultures, then it can't be via transduction. So the only remaining answer is via transformation.

34. Which of the following traits do archaeans and bacteria share?ANSWER: B. 2 and 3

Basically, because bacteria have peptidoglycan in the cell wall and archaens do not, the composition of the cell wall is different, so 1 can't be it, mak ing a and e incorrect. And both bacteria and archaea have a plasma membrane, so 2 is correct and c is therefore incorrect (doesn't include 2) then, both lack a nuclear envelope so 3 is correct, and the only b includes both 2 and 3 so that must be the correct answer. And 4 just doesn't make sense so it can't be d either

36. Jams, jellies, preserves, honey and other foodstuffs with a high sugar content hardly ever become contaminated by bacteria, even whent he food containers are left open at room temperature. This is because bacteria that encounter such an environment.ANSWER: B. undergo death by plasmolysis

Because the foodstuffs have such a high sugar concentration, the water from the bacteria would leave the bacteria cell and goes into the jam because it's hypotonic and so the cell undergoes plasmolysis and dies.

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